Serious Explorations Ford Explorer and Ranger Message Board
#1 Resource for Ford Explorer and Ranger Owners - By Enthusiasts, for Enthusiasts.


Ford Explorer Generation Guide

EF Swag Store 2016 Ford Explorer Forums Elite Membership Chat Room My Posts Reviews Explorer Photo Gallery
Go Back   Ford Explorer and Ranger Forums "Serious Explorations" > Ford Explorer Ranger Repair - Troubleshooting - Modifications & Detailing Forums > 1991 - 1994 Explorer Ranger Navajo 1st Generation > Stock 1991 - 1994 Explorers

Notices

Stock 1991 - 1994 Explorers For questions related to the base Ford Explorer. Problem solving, maintenance, TSB, service bulletins, owner reviews, specifications. No modification questions.

Code 172 after changing O2 sensors.

Reply
 
Thread Tools
Old 06-15-2010, 01:16 AM   #1
mechjames
Elite Explorer
Richmond, BC
 
mechjames's Avatar
1994 Explorer XLT
 
Join Date: Sep 2007
Posts: 490

Vehicle Specs

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
(Original Poster)
Code 172 after changing O2 sensors.

HEGO sensor circuit indicates system lean (right side)


I did reset the computer before I changed the o2 sensors. I thought it might be a good thing to do because i'm approaching 300,000 km and i'm unsure if they have been done in the past, and the concensus on here is that it seems to reduce mileage and power and not throw a CEL, because the EEC-IV has too much tolerance in O2 sensor readings, or the sensors just get lazy.

I left the battery unplugged the night before I changed them. All seems well and it drives well but it throws a Code 172 a few minutes after driving. CEL seems to come and go as you're driving at first, but after that first few minutes when it comes on, it seems to stay on now.

No KOEO off codes.

Do I have a dud o2 sensor? Or is it just detecting a lean condition on the passenger's side? It seems to drive really great, but I won't know if i'm saving gas until I fill up the tank.




__________________
-1994 Explorer XLT Green, 208,000km, 5.5" duff lift, 35" BFG All Terrains, 4.0L 5 speed, manual shift T Case, KKM Air Intake

-1994 Explorer XLT Black.[298,100km]
Retired
mechjames is offline   Reply With Quote
( Join the Elite Explorers )

Join the Elite Explorers for only $20 a year. Explorer Forum has probably saved you that much already, and will continue to save you money as you learn how to diagnose and fix problems yourself, and learn which modifications really work without having to experiment on your own. Elite Explorer members can change the forum "styles" to eliminate most ads, including blue underlined links, and no ads on photos. Other benefits include the ability to store 1000 Private Messages, upload photo attachments directly to your posts and to our Photo Gallery and more. Join the Elite Explorers today.


Old 06-15-2010, 01:26 AM   #2
BrooklynBay
Brooklyn, NY
 
BrooklynBay's Avatar
88 89 93 95 96 Aerostars
 
Join Date: Nov 2005
Posts: 48,103

Vehicle Specs

Mentioned: 4 Post(s)
Tagged: 1 Thread(s)
Quoted: 217 Post(s)
Did you check the wiring to see if any insulation is melted, and shorted to the exhaust system?
BrooklynBay is offline   Reply With Quote
Old 06-15-2010, 01:32 AM   #3
mechjames
Elite Explorer
Richmond, BC
 
mechjames's Avatar
1994 Explorer XLT
 
Join Date: Sep 2007
Posts: 490

Vehicle Specs

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
(Original Poster)
Quote:
Originally Posted by BrooklynBay View Post
Did you check the wiring to see if any insulation is melted, and shorted to the exhaust system?
Will check in the morning. Wiring from the connector to the harnesses were fine when I changed it.

I'm assuming you mean the wires that run from the connector to the sensor itself.

I don't think that the wires would have shorted so quick, because even on my first test drive, the CEL came on pretty quick. I will check it tomorrow.

I didn't have a CEL before doing the O2's.




__________________
-1994 Explorer XLT Green, 208,000km, 5.5" duff lift, 35" BFG All Terrains, 4.0L 5 speed, manual shift T Case, KKM Air Intake

-1994 Explorer XLT Black.[298,100km]
Retired
mechjames is offline   Reply With Quote
Old 06-15-2010, 03:36 AM   #4
rhauf
Ca
'93 and '91 explorer
 
Join Date: Nov 2005
Posts: 1,238

Vehicle Specs

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
make sure the connectors, where the o2 sensors plug in are making a good connection. sometimes they get corroded and don't connect well. plug them in and out a few times, use dielectric grease etc.
rhauf is offline   Reply With Quote
Old 06-15-2010, 09:06 PM   #5
TedJ
Fair Lawn, NJ
'94 Sport
 
Join Date: Dec 2006
Posts: 879

Vehicle Specs

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
What brand sensor did you use?

Try putting the original back in and see what happens. After all the pre-broken for my inconvenience parts I have gotten I would not be surprised if it was defective or something.
TedJ is offline   Reply With Quote
Old 06-15-2010, 10:55 PM   #6
mechjames
Elite Explorer
Richmond, BC
 
mechjames's Avatar
1994 Explorer XLT
 
Join Date: Sep 2007
Posts: 490

Vehicle Specs

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
(Original Poster)
Quote:
Originally Posted by TedJ View Post
What brand sensor did you use?

Try putting the original back in and see what happens. After all the pre-broken for my inconvenience parts I have gotten I would not be surprised if it was defective or something.
Bosch Premium Direct Fit. Bosch supposidely makes the OEM sensors for Ford. They looked damn near identical.




__________________
-1994 Explorer XLT Green, 208,000km, 5.5" duff lift, 35" BFG All Terrains, 4.0L 5 speed, manual shift T Case, KKM Air Intake

-1994 Explorer XLT Black.[298,100km]
Retired
mechjames is offline   Reply With Quote
Old 06-16-2010, 01:22 PM   #7
Reejerey
SLC UT
92 XL 2 dr 4x4 manual
 
Join Date: Jan 2009
Posts: 140

Vehicle Specs

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
possibly an exhaust leak in around the o2 sensor
Reejerey is offline   Reply With Quote
Old 06-16-2010, 02:06 PM   #8
TedJ
Fair Lawn, NJ
'94 Sport
 
Join Date: Dec 2006
Posts: 879

Vehicle Specs

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Obviously check for an exhaust leak.....

Bosch should be good, but it's hard not to suspect the replacement part if you have a problem you didn't before installing it. Try swapping them side for side or with the old one. If the code changes to one for the other side or goes away with the old one back in, go and complain that it is a dud.
TedJ is offline   Reply With Quote
Old 06-16-2010, 02:56 PM   #9
mechjames
Elite Explorer
Richmond, BC
 
mechjames's Avatar
1994 Explorer XLT
 
Join Date: Sep 2007
Posts: 490

Vehicle Specs

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
(Original Poster)
Quote:
Originally Posted by TedJ View Post
Obviously check for an exhaust leak.....

Bosch should be good, but it's hard not to suspect the replacement part if you have a problem you didn't before installing it. Try swapping them side for side or with the old one. If the code changes to one for the other side or goes away with the old one back in, go and complain that it is a dud.
I do have a tiny exhaust leak, but it's downstream of the O2 sensor. I had to cut the Y pipe 2 years ago to get the transmission out and welded it back together. Just a tiny little tick, but it's not before the o2 sensor, it's after.

I will just go and exchange it, the parts store is good to me. It wouldn't be worth my time to switch the sides, it's hard enough trying to unplug and plug it back in behind the engine.

If it still shows a code with a new sensor, then i'll switch sides and see if the code follows.




__________________
-1994 Explorer XLT Green, 208,000km, 5.5" duff lift, 35" BFG All Terrains, 4.0L 5 speed, manual shift T Case, KKM Air Intake

-1994 Explorer XLT Black.[298,100km]
Retired
mechjames is offline   Reply With Quote
Reply


Suggest this thread to friends:



Join the "Elite Explorers" Today!



Search Explorer Forum


Top of Page

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 04:57 AM.



US Flag
We Support Our Troops!

Explore the site!


Copyright 2014 - 1996 Rick Horwitz Photography



Ford Motor Company is not involved in the management of this site in any way.



All tips on this site are for use at your own risk and discretion.

Modifying the suspension on any vehicle will cause changes to its handling characteristics.



Vendor Tools vBulletin Plugins by Drive Thru Online, Inc.